Netscape came to the conclusion that a more dynamic World Wide Web was necessary, i.e. a programming language alongside HTML. They wanted to enable web designers and programmers more space for more plugins and images with a directly entered code in the markup of the web page. As they progressed with Eich, they figured out that the new programming language would complement Java and it meant the exclusion of other languages (Python, for example, and others). Server-side implementations were developed and added in the new millennium.
Standardization and Specification
How Does It Work?